Positioner methods and apparatus

ABSTRACT

This invention relates to methods and apparatus for controlling the positioning of a device such as a fluid control valve. Hydraulic cylinder means having a movable piston disposed therein are provided operably connected to the device. The device is positioned manually at a desired setting, and upon the receipt of and in response to a physical signal a control signal is generated which is utilized to cause the introduction of pressurized hydraulic fluid into the hydraulic cylinder means on a selected side of the movable piston thereby moving the piston and the device in a desired direction and displacing hydraulic fluid on the other side of the piston. The displaced hydraulic fluid is stored throughout the duration of the physical signal, and upon the withdrawal thereof, the stored hydraulic fluid is reintroduced into the hydraulic cylinder means on the side of the piston from which it was displaced thereby restoring the piston and the device to the setting occupied prior to the receipt of the physical signal.

United States Patent Jameson Sept. 23, 1975 POSITIONER METHODS AND-APPARATUS [75] Inventor: Douglas L. Jameson, Duncan, Okla. ABSTRACT [73] Assigneez Halliburton Company, Duncan This invention relates to methods and apparatus for Okla controlling the positioning of a device such as a fluid control valve. Hydraulic cylinder means having a movl Filedi 20,1974 able piston disposed therein are provided operably [211 App]. NOJ 534,848 connected to the device. The device is positioned manually at a desired setting, and upon the receipt of and in response to a physical signal a control signal is generated which is utilized to cause the introduction 60/413; 175/24; 175/40; 137/236 of pressurized hydraulic fluid into the hydraulic cylinlnt. CLZ t de means on a Selected ide of the movable piston of Search thereby moving the piston and the device in a desired 60/398;91/1 R, 391 R; 175/24, 40; 137/236 direction and displacing hydraulic fluid on the other side of the piston. The displaced hydraulic fluid is References Cited stored throughout the duration of the physical signal, UNlTED STATES PATENTS and upon the withdrawal thereof, the stored hydraulic 2,371,893 3 1945 Hyland 60/387 x fluid is reintroduced into the-hydraulic Cylinder means 2,473,507 6/1949 Bullard 60/387 011 the Side of the Piston from which it was displaced 2,613,703 10/1952 Calvert .1 60/387 X thereby restoring the piston and the device to the set- 3,572,208 3/1971 Mott a 91/1 Primary Examiner-Edgar W. Geoghegan Attorney, Agent, or FirmJohn H. Tregoning ting occupied prior to the receipt of the physical signal.

11 Claims, 4 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of 4 3,906,726

US Patent Sept. 23,1975 Sheet 3 of4 3,906,726

u d i W. U o E 0 a m. W F z 5 0A 0 WV HV M. H UL 070 l- C 1 0A W M 7 u m 2 LE W7 W "M 4 N N E L U5 AMHO MP M 6 m 4/ 45 MD M W a a 1 w 0 3 HC 7. v W W I... 0 r A 6 A w 8 4n W w P w w 5 M L P c w WW 0w" M 0 mm A FLU/D ACCUMUMTOR W50 MEMORY ACCUMULA 7'01? DISABLE VAL VE- POSITIONER METHODS AND APPARATUS This invention relates to a positioner apparatus and methods of positioning a device such as a fluid control valve or choke. In many applications, it is desirable to manually position a device at a desired setting but automatically change the setting in response to a physical signal indicating an abnormal condition requiring such change. For example, in the drilling and completion of well bores which penetrate subterranean formations, the control of the pressure of fluid within the annulus between the well bore and a drill string extending thereinto is often advantageous. That is, it is often desirable to control the pressure exerted at the bottom of a well bore being drilled by holding a back pressure on the column of drilling mud in the annulus at the well head. The back pressure in combination with the hydrostatic head exerted on the column of the well bore by the column of mud contains the pressure of fluids within the formations penetrated by the well bore, i.e., prevents such fluids from flowing into the well bore and up the annulus, a condition commonly referred to as kicking.

Heretofore, it has been the usual practice to provide a choke in a manifold connected with the annulus between the well bore and a drill string beneath a closed blowout preventer. In the event of a kick, i.e., a formation is penetrated containing fluids under pressure greater than the hydrostatic head of the drilling mud in combination with the back pressure held thereon, the choke is utilized to contain the pressure as heavier mud is circulated 'down the drill string and up the annulus to bring about an increase in pressure on the kicking formation whereby it is contained. The choke must be regulated in a manner such that excessive back pressure is not exerted in the annulus which would damage equipment or the formation or cause sticking of the drill string. By the present invention positioner apparatus and methods of positioning a device are provided which are particularly suitable for controlling the operation of a choke used to control the back pressure maintained in a well bore during drilling operations in that the invention provides for the manual positioning of the choke, but in the event ofa kick, the choke is au tomatically quickly opened to relieve excess pressure from the annulus and upon the relief of such pressure, the choke is returned to its original setting. However, as will be understood by those skilled in the art, the methods and apparatus of the present invention are readily adaptable to many various other applications wherein it is desirable to manually control the positioning of a device, but automaticallymove the device to a different position in response to a physical signal and then automatically return the device to its original position upon the'withdrawal of the signal.

The method of the present invention'relates to automatically changing the position of a device operated by manually controllable hydraulic cylinder means in response to a physical signal, and then repositioning the device to its original setting upon the withdrawal of the physical signal which basically comprises the steps of generating a control signal in response to the physical signal, utilizing the control signal to override the manual control of the device and introduce pressurized hydraulic fluid into the hydraulic cylinder means on a selected side of the movable piston therein to move said piston and the device in a desired direction and to displace hydraulic fluid from the other side of the piston, storing the hydraulic fluid displaced from the hydraulic cylinder means throughout the duration of the physical signal, and then reintroducing the stored hydraulic fluid into the hydraulic cylinder means on the side of the piston therein from which it was displaced thereby restoring the piston and the device to the position occupied prior to the receipt of the physical signal. Positioner apparatus for carrying out the method is also provided by the invention, i.e., apparatus for manually positioning a device, but automatically moving the device to a different position in response to a physical signal and then repositioning the device to its original position upon termination of the physical signal.

In the drawings forming a part of this disclosure:

FIG. 1 is a diagrammatic illustration of a well bore and apparatus for drilling the well bore including a choke connected to the annulus beneath a blowout preventer and the positioner apparatus of the present invention;

FIG. 2 is a schematic illustration of the positioner apparatus of the present invention shown connected to the choke of FIG. 1',

FIG. 3 is a portion of the apparatus of FIG. 2 illustrating the operation of the apparatus upon the receipt of a physical signal; and

FIG. 4 illustrates the operation of the apparatus of FIG. 3 upon the withdrawal of the physical signal.

Referring now to FIG. 1, an example of the application of the methods and apparatus of the present invention for manually positioning a device, but automatically changing the position of the device in response to the receipt of a physical signal, and then repositioning the device to its original position upon the withdrawal of the signal is illustrated. More particularly, a well bore 10 and conventional apparatus for drilling the well bore are illustrated schematically. A string of drill pipe 12 is disposed in the well bore having a conventional drill bit 14 attached to the lower end thereof. The string of drill pipe 12 is rotated by a rotary drilling rig (not shown) positioned on the surface above the well bore 10. A conventional blowout preventer 16 is provided at the surface which is closed about the drill string thereby preventing pressure in the annulus between the well bore 10 and the drill string 12 from escaping. During drilling operations, drilling mud is circulated downwardly through the drill string 12, through the drill bit 14, and upwardly through the annulus between the drill string and well bore. A conduit or manifold 18 is connected to the surface pipe 20 beneath the blowout preventer 16 in sealed communication with the annulus. A conventional shutoff valve 22 is disposed in the conduit 18 and the conduit 18 is connected to the inlet of a conventional choke 24. The positioner apparatus of the present invention, generally designated by the numeral 26, which will be described in detail hereinbelow, is operably connected to the choke 24 and is connected to the choke manifold 18 upstream of the choke 24 by a control signal conduit 25. As will be described further, the pressure of fluids contained in the choke manifold 18 upstream of the choke 24 is monitored by the apparatus 26 so that when an over-pressure condition exists in the manifold and in the well bore 10, the apparatus 26 overrides the manual control of the choke 24 and opens it to relieve such excess pressure. The outlet of the choke 24 is connected by a conduit 28 to a conventional gas-drilling mud separator 30. Gas separated in the separator 30 is withdrawn therefrom by way of a conduit 32 connected thereto and separated liquids and solids are withdrawn from the separator 30 by way of a conduit 34 attached thereto. The conduit 34 is connected to a conventional shale shaker 36 wherein cuttings are separated from the drilling mud. The separated drilling mud flows by way of a conduit 38 into a mud pit 40. Drilling mud is withdrawn from the pit 40 by way of a conduit 42 which is connected to one or more conventional mud pumps 44. From the pumps 44 the drilling mud is circulated back into the drill string 12 by way of a conduit 46 connected thereto.

In operation of the well bore drilling apparatus described above and as is well understood by those skilled in the art, when a kick is encountered it is the usual practice to stop the mud pumps 44 and close the choke 24 so that the shut-in pressure upstream of the choke can be observed. The mud pump 44 is then started and the choke gradually opened to maintain a back pressure at a level above the shut-in pressure. Upon reaching the desired mud circulation rate, the choke is continuously adjusted to maintain the pressure at a con stant level until the kick is circulated out of the annulus. That is, formation fluids are circulated up the annulus with the drilling mud through the choke 24, into the separator 30 where formation gases are separated from the drilling mud, through the shale shaker 36 and into the mud pit 40 from where the drilling mud is circulated back to the bottom of the well bore by way of the mud pumps 44 and the drill string 12. After the kick has been circulated out of the annulus heavier mud is pumped into the drill string and well bore to contain the kicking formation.

The positioner apparatus 26 of the present invention allows the operator or driller to control the choke 24 manually when making pressure adjustments but over rides the manual control during a kick or other overpressure circumstance and provides automatic operation of the choke to prevent over-pressure conditions in the annulus and the well bore from occurring. That is, the apparatus 26 automatically causes the choke to open quickly in response to predetermined conditions of pressure within the annulus and choke manifold and upon return of the pressure to a predetermined normal level the apparatus 26 automatically repositions the choke 24 to its original setting and returns the apparatus to manual control.

Referring now to FIGS. 2 through 4, the positioner apparatus 26 connected to the choke 24 is illustrated diagrammatically. In FIGS. 2 through 4, conduits carrying hydraulic fluid are indicated by solid lines and conduits carrying air pressure are indicated as dashed lines. As will be understood, the choke 24 can be any valve or other device which can be positioned by hydraulic cylinder means, i.e., lineal movement of a control arm or other operating member, and this invention is not to be limited to the specific well bore drilling application given by way of example.

The apparatus of the invention includes a conventional hydraulic cylinder means 50 having a movable piston 52 disposed therein operably connected to the inner valve 54 of the choke 24 by an operator rod 56. The hydraulic cylinder means 50 generally comprises a closed cylinder 58 within which the piston 52 is slidably but sealingly disposed in a conventional manner. Hydraulic fluid ports 60 and 62 are positioned at opposite ends of the cylinder 58 through which hydraulic fluid is injected or withdrawn on opposite sides of the piston 52. A pair of conduits 64 and 66 are connected to the ports 60 and 62 respectively and to two of the ports of a four-way manual control valve 68. The manual control valve 68 is used for selectively supplying hydraulic fluid to one side of the piston 52 within the cylinder 58 and exhausting it from the other side, thereby controlling the movement of the piston 52 and positioning the inner valve 54 of the choke 24 at desired settings. A conduit 70 is provided connecting a port of the four-way valve 68 to the discharge of an air operated hydraulic pump 72. The air operator of the pump 72 is connected to an air supply header 152 by a conduit 192. A conventional air pressure regulator 194 is disposed in the conduit 192 for adjusting the pressure of the air supplied to the pump 72 and the speed thereof. The suction connection of the pump 72 is connected by a conduit 74 to a hydraulic fluid accumulator 76. As will be understood, the pump 72 produces a stream of pressurized hydraulic fluid which whenintroduced on one side of the piston 52 within the cylinder 58 provides the force required for moving the piston 52 and the inner valve 54 of the choke 24. A conduit 78 connects a port of the four-way valve 68 with the hydraulic fluid accumulator and functions to return hydraulic fluid displaced from the hydraulic cylinder means 50 to the accumulator 76.

An air pressure operated manual control disable valve 80 is provided disposed in the conduits 70 and 78 between the four-way valve 68, the hydraulic pump 72 and the hydraulic fluid accumulator 76.

A manually operable hydraulic pump 82 is provided connected to the hydraulic fluid accumulator 76 by a conduit 84. The discharge of the pump 82 is connected by a conduit 86 to the conduit 70 between the valves 68 and 80. As will be understood, the manually operably hydraulic pump 82 is provided for use in the event of an air supply failure or other condition causing the air operated hydraulic pump 72 to become inoperable. That is, the hydraulic cylinder means 50 and choke 24 can be positioned by manual activation of the hydraulic pump 82 if the air operated pump 72 fails.

A memory acculumator means generally designated by the numeral 90 is provided comprised of an elongated cylinder 92 having a forward end 91 and a rearward end 93 and having a piston 94 slidably and sealingly disposed therein. The cylinder 92 is closed at both ends except for an opening in the end 91 through which an activator arm 96 extends which is connected to the piston 94. The opening in the end 91 of the cylinder 92 through which the activator arm 96 passes includes conventional means (not shown) for sealing against the outside surfaces of the activator arm 96 so that the activator arm 96 is free to slide through the opening but hydraulic fluid contained within the cylinder 92 is prevented from escaping therefrom. A force activated two-way valve 98 is provided, the function of which will be described below, positioned with respect to the exterior end of the activator arm 96 so that when the activator arm is fully extended it contacts and switches the position of the valve 98. Conversely, when the activator arm 96 is withdrawn from contact with the valve 98 its position is reversed.

The cylinder 92 of the memory accumulator means 90 includes a pair of ports 100 and 102 positioned at the ends 93 and 91 of the cylinder 92 respectively for introducing and withdrawing hydraulic fluid on opposite sides of the piston 94. A conduit 104 is provided connecting the port 102 of the cylinder 92 with a port of an air pressure operated two-way valve 106. a conduit 108 connects a port of the valve 106 to the cond it 64 previously described which is connected to the port 60 of the hydraulic cylinder means 50. A conduit 110 is connected to a port of the valve 106 and to a hydraulic fluid exhaust header 112 which returns exhausted hydraulic fluid to the hydraulic fluid accumulator 76. The port 100 disposed in the cylinder 92 of the memory accumulator means 90 is connected by a conduit 114 to a port of an air pressure operated two-way valve 1 16, the function of which will be described hereinbelow. A

conduit 118 connects a port of the valve 1 16 to the discharge of the previously described air operated hydraulic pump 72, and a conduit 120 connects a port of the valve 116 to the hydraulic fluid exhaust header 1 12. An air pressure operated two-way valve 122, the function of which will be described below, is provided, a port of which is connected to a port of a valve 1 16 by a conduit 124. A conduit 126 connects a port of the valve 122 with the conduit 66 previously described which is connected to the port 62 disposed .the cylinder 58 of the hydraulic cylinder means 50. A conduit 128 connects a port of the valve 122 to the hydraulic fluid exhaust header 112.

A pressure comparator means 130 is provided for receiving a pressure physical signal'by way of the conduit connected thereto and generating a pneumatic or air pressure control signal which operates the valves 80, 106, 116 and 122. The pressure comparator means 130 is comprised of a housing 132 divided into two separate sealed compartments 134 and 136 by a flexible diaphragm member 138. A side of the housing 132 forming the compartment 136 includes a cylinder 140 connected thereto and connected to the control signal conduit 25. A piston 142 is slidably disposed in the cylinder 140 including conventional means for providing a sliding seal against the inside surfaces of the cylinder 140. A piston rod 144 connects the inward side of the piston 142 to the diaphragm 138. As will be understood, in the well bore drilling application described above, the conduit 25 connects the cylinder 140 to the conduit 18 in which the choke 24 is disposed upstream of the choke so that a physical signal indicating the I pressure level in the annulus of the well bore 10 is communicated to the cylinder 140 and piston 142. An activator arm 146 is disposed in the sealed chamber 134 of the housing 132 attached to the opposite side of the diaphragm 138 from the piston rod 144 and extending in a conventional sealed manner through the housing 132 to the exterior thereof. The housing 132 includes a port 148 disposed therein communicating with the chamber 134. A conduit 150 connects the port 148 to the air supply header 152 which is in turn connected to a source of pressurized air. A conventional downstream pressure regulator 154 is disposed in the conduit 150 and a conventional pressure indicator 156 is connected to the conduit 150 downstream of the air regulator 154.

A force activated two-way valve 158 is provided positioned with respect to the exterior end of the activator arm 146 such that when the activator arm is moved outwardly from the housing 132 the end thereof contacts the valve 158 switching its position. Conversely, when the activator arm 146 is withdrawn from contact with the valve 158 its position is reversed.

The relative areas of the diaphragm 138 and exterior surface of the piston 142 of the pressure comparator means 130 are such that 1 psig of air pressure within the chamber 134 balances psig of fluid pressure exerted on the exterior surface of the piston 142 by the pressure physical signal communicated with the cylinder 140. Thus, if it is desired to set the pressure comparator so that it activates the valve 158 at a physical pressure signal exceeding 500 psig, 5 psig of air pressure is introduced to the interior of the chamber 134 by way of the air pressure regulator 154. In this example, when the pressure physical signal communicated to the piston 142 reaches a level above 500 psig, the piston 142, piston rod 144, the diaphragm 138, and the activator rod 146 are moved in a direction toward the valve 158, contacting and switching the position thereof. The switching of the valve 158 generates an air pressure control signal in a manner which will be described hereinbelow.

A port 160 is provided in the housing 132 of the pressure comparator means 130 communicating with the sealed chamber 136 therewithin. A conduit 162 is connected to the port 160 and to a port of a manually operated normally closed two-way test valve 164. The valve 164 is connected by a conduit 166 to a port of a manually operated normally open two-way disable valve 168 by a conduit 166. The valve 168 is in turn connected to the air supply header 152 by a conduit 170.

When it is desired to test the operation of the apparatus 126, the test valve 164 is manually switched which causes air pressure from the header 152 to flow by way of the conduit 170, the normally open disable valve 168, the conduit 166, the test valve 164, and the conduit 162 into the sealed chamber 136 within the housing 132 of the pressure comparator means 130. The build-up of air pressure in the chamber 136 simulates an increase in the physical pressure signal by moving the diaphragm 138 and activator arm 146 into contact with the two-way valve 158.

As will be understood by those skiled in the art, the pressure comparator means 130 and the valve 158 can take a variety of forms other than the apparatus described. For example, any number of conventional instruments which sense a physical signal and produce a pneumatic control signal in accordance therewith can be substituted for the apparatus. Further, the apparatus 26 can be responsive to physical signals other than pressure and control signals generated by other instruments monitoring process variables such as composition, flow, temperature, etc. can be monitored.

The outlet port of the disable valve 168, in addition to being connected to the testvalv'e 164 by the conduit 166 is connected to an inlet port of the valve 158 by a conduit 172 and to an inlet port of the valve 98 by a conduit 174. An air pressure header 176 is provided which is connected to the air pressure operator of the manual control disable valve 80 by a conduit 178. The air pressure operator of the valve 106 is connected to the header 176 by a conduit 180, and the air pressure operator of the valve 122 is connected thereto by a conduit 182. A port of the force activated valve 98 is connected to the header 176 by a conduit 184. The header 176 includes a check valve 186 disposed therein, and a conduit 188 connects to the header 176 upstream of the check valve 186 and to a port of the valve 158. A conduit 190 connects the air pressure operator of the valve 116 to the conduit 188.

Operation In operation of the apparatus 26 in the well bore drilling application described above and illustrated in FIG. 1, the manual choke control valve 68 is utilized to manually position the choke 24 at a desired setting. That is, when the apparatus 26 is in the manual control mode as illustrated in FIG. 2, the four-way valve 68 is manually adjusted so that pressurized hydraulic fluid pumped from the hydraulic fluid accumulator 76 by the pump 72 or the pump 82 flows through the conduit 70, through the normally open manual control disable valve 80, through the conduit 70 and the valve 68 and through either the conduit 64 or 66 and ports 60 and 62 into the cylinder 58 of the hydraulic cylinder means 50 on a selected side of the piston 52 disposed therein. As will be understood, when pressurized hydraulic fluid is introduced on one side of the piston 52 by means of one of the conduits 64 or 66, hydraulic fluid contained in the cylinder 58 on the other side of the piston 52 is displaced therefrom by way of the other of the conduits 64 or 66, through the valve 68, through the conduit 78 and through the disable valve 80 into the hydraulic fluid accumulator 76.

Once the choke 24 is positioned at a desired setting, the air regulator 154 disposed in the conduit 150 connected to the air supply header 152 is manually adjusted to introduce air pressure into the chamber 134 of the pressure comparator means 130. Assuming that it is desired that the apparatus 26 override the manual control setting of the choke 24 when the pressure upstream of the choke 24 exceeds 500 psig, then the air regulator 54 is adjusted so that the pressure indicator 156 indicates a downstream pressure of psig, thereby indicating that 5 psig is maintained within the chamber 134 of the pressure comparator means 130.

in this mode of communication, air pressure from the air supply header 152 is communicated by way of the conduit 170 through the normally open disable valve 168 to the normally closed test valve 164 by way of the conduit 166. Air pressure from the header 152 is also communicated to the normally closed valve 158 by way of the conduit 172 and to the valve 98 by way of the conduit 174 which is maintained in the closed position by the activator arm 96 of the memory accumulator means 90. The ports of the air pressure operated valves 106 and 122 connected to the conduits 108 and 126 are in the closed position. Thus, in the manual control mode, the manual choke control valve 68 can be manually adjusted to change the setting of the choke 24, and so long as the physical signal entering the cylinder 140 of the pressure comparator means 130 does not exceed 500 pounds the apparatus 26 remains in the manual control mode. 1

Referring now to FIG. 3, let it be assumed that the physical signal communicated with the cylinder 140 of the pressure comparator means 130, i.e.. the annulus and choke upstream pressure, exceeds 500 psig. When this pressure condition exists, the force exerted on the piston 142 exceeds the force exerted on the flexible diaphragm 138 by the 5 psig air pressure maintained in the chamber 134 which causes the activator arm 146 to contact the valve 158 switching the position of the valve 158 and communicating the conduit 172 attached thereto with the conduit 188. As a result, air pressure flows through the valve 158 from the conduit 172 and into the header 176. Air pressure also flows from the conduit 188 by way of the conduit 190 to the air operator of the valve 116 switching its position as shown in FIG. 3. Simultaneously, air pressure flows from the header 176 through the conduits 178, 180 and 182 to the air operators of the valves 80, 106, and 122 respectively switching their positions as shown in FIG. 3.

The switching of the manual control disable valve closes the conduits 70 and 78 whereby hydraulic fluid cannot flow to or from the manual control valve 69 thereby overriding or disabling the control valve 68.

The switching of the valve 116 communicates the conduit 118 connected to the discharge of the hydraulic fluid pump 72 to the conduit 124. The conduit 124 connects between the valve 116 and the valve 122 and the switching of the valve 122 communicates the conduit 124 with the conduit 126 which is connected to the conduit 66. Thus, with the switching of the valves 116 and 122 pressurized hydraulic fluid from the pump 72 flows byway of the conduit 118, the valve 116, the conduit 124, the valve 122, the conduit,l26, the conduit 66 and the port 62 into the housing 58 of the hydraulic cylinder means 50 moving the piston 52 disposed therein and opening the choke 24.

The hydraulic fluid contained within the housing 58 of the hydraulic cylinder means 50 on the other side of the piston 52 is displaced out of the cylinder 58 by way of the port 60 into the conduit 64. From the conduit 64 the displaced hydraulic fluid flows by way of the conduit 108 to the valve 106. With the switching of the valve 106, the conduit 108 is communicated with the conduit 104 connected thereto so that the displaced hydraulic fluid flows through the valve 106, through the conduit 104, through the port 102 disposed in the housing 92 of the memory accumulator means and into the housing 92 on the side of the piston 94 to which the activator arm 96 is attached. The introduction of the displaced hydraulic fluid into the housing 92 moves the piston 94 toward the end 93 thereof which displaces hydraulic fluid contained in the housing 92 on the other side ofthe piston 94 out of the housing 92 by way'of the port into the conduit 114. With the switching of the valve 116, the conduit 114 is communicated with the conduit which is in turn attached to the hydraulic fluid exhaust header 112. Thus, hydraulic fluid displaced from the cylinder 92 of the accumulator means 90'flows through the valve 116, through the conduits 120 and 112 and into the hydraulic fluid accumulator 76.

The movement of the piston 94 disposed in the housing 92 of the memory accumulator 90 causes the activator arm 96 to bc moved out of contact with the valve 98 which switches the position of the valve 98 thereby communicating the conduit 184 attached thereto and attached to the air header 176 with the conduit 174 attached thereto and attached to the air supply header 152 by way of the normally open disable valve 168.

As will be understood, so long as the physical pressure signal communicated with the cylinder 140 of the pressure comparator means exceeds 500 psig. the introduction of pressurized hydraulic fluid through the port 62 disposed in the housing 58 of the hydraulic cylinder means 50 continues and the piston 52 is moved to the full extent possible in the direction opening the choke 24. The hydraulic fluid displaced on the other side of the piston 52 from the housing 58 flows into the memory accumulator means 90 and is stored in the memory accumulator 90 untilflthe physical signal communicated with the cylinder 140 of the pressure comparator means 130 drops below 500 psig.

As will be understood, the opening of the choke 24 increases the flow rate of fluids passing therethrough which lowers the pressure level upstream of the choke 24 and in the annulus of the well bore 10 as well as the pressure signal communicated to the cylinder 140 of the pressure comparator means 130. i

Referring now to FIG. 4, when the pressure level of the physical signal communicated with the cylinder 140 decreases to a point below 500 psig, the 5 psig pressure level in the compartment l34'of the pressure comparator means 130 causes the activator arm 146, the piston rod 144 and the piston 142 to move in a direction such that the activator arm 146 ismoved out of contact with the valve 158. This in turn causes the valve 158 to switch positions so that the port thereof connected to the conduit 172 is shut off and the port connected to the conduit 188 is opened to the atmosphere. The opening of the conduit 188 to the atmosphere causes air pressure contained therein to exhaust which in turn exhausts air pressure from the conduit 190 attached to the conduit 188 and'from the air operator of the valve 116 causing the valve 116 to switch positions. At this point, air pressure is still supplied to the air header 176 by way of the normally open valve 168, the conduit 174, the valve 98 and the conduit 184. The check valve 186 prevents the air header 176 from being exhausted by way of the conduit 188. Thus, when the physical pressure signal communicated with the cylinder 140 of the pressure comparator means 130 drops below 500 psig, the valve 116 is switched but the valves 80, 106 and 122 are not switched.

The switching of the valve. 116 communicates the conduit 118 connected to the discharge of the hydraulic fluid pump 72 with the conduit 114 which is connected to the port 100 disposed in thehousing 92 of the memory accumulator means 90 so that pressurized hydraulic fluid is introduced into the cylinder 92 by way of the port 100. The introduction of pressurized hydraulic fluid into the cylinder 92 moves the piston 94 disposed therein toward the end 91 thereof which displaces the stored hydraulic fluid on the other side of the piston 94 out of the housing 92 by way of the port 102 into the conduit 104. From the conduit 104, the hydraulic fluid displaced from the cylinder 92 flows through the valve 106, the conduit 108, the conduit 64, the port 60 disposed in the housing 58 of the hydraulic cylinder means 50 into the housing 58 causing the piston 52 disposed therein to be moved in a direction closing the valve 24.

As will now be apparent, the introduction of pressurized hydraulic fluid into the memory accumulator means 90 by way of the port 100 disposed in the housing 92 thereof continues until the piston 94 is moved toward the end 91 thereof to the full extent which causes all of the hydraulic fluid stored therein to be displaced back into the cylinder 58 of the hydraulic cylinder means 50. Once the piston 94 of the memory accu mulator means 90 reaches the end of its travel, all of the hydraulic fluid displaced therefrom is transferred back into the cylinder 58 of the hydraulic cylinder means 50 and the choke 24 is returned to the setting it occupied prior to the increase in the physical pressure signal above 500 psig.

Referring again to F IG. 2, when the piston 94 reaches the end of its travel, the activator arm 96 attached thereto contacts the valve 98 switching its position. The changed position of the valve 98 communicates the conduit 184 attached to the air header 176 with the conduit 196 connected thereto and to the conduit 190. This causes air pressure within the header 176 to be exhausted: by way of the conduit 184, the valve 98, and the conduits 196, 190 and 188 through the valve 158 to the atmosphere. The exhausting of the header 176 in turn exhausts air pressure by way of the conduits 178, 180 and 182 from the air operators of the valves 80, 106 and 122 respectively, which returns the apparatus 26 to the manual control mode. That is, the disable valve is opened so that pressurized hydraulic fluid is communicated with the manual control valve 68 and hydraulic fluid exhausted through the valve 68 is free to flow by way of the conduit 78 to the hydraulic fluid accumulator 76. The switching of the valves 106 and 122 closes the ports connected to the conduits 108 and 126.

An indicator 198 which visually indicates the presence of air pressure is connected to the conduit 184 so that when air pressure is present in the header 176 the indicator 198 indicates such fact and the operator of the apparatus 26 is made aware that the apparatus 26 is on automatic and the manual choke control valve 68 is disabled.

The disable valve 168 can be manually switched at any time and functions to prevent the apparatus 26 from automatically overriding the manual control valve 68 and opening the choke 24. That is, when the disable valve 168 is switched, the air header 176 and other air conduits connected thereto are exhausted. Thus, if an over-pressure condition exists, but the operator of the apparatus 26 desires to control the choke 24 manually, he can disable the automatic override feature of the apparatus 26 by use of the valve 168 and maintain the apparatus 26 in the manual control mode.

When it is desired to test the apparatus 26 and simulate the receipt of a physical signal activating the automatic override thereof, the test valve 164 is manually switched which communicates air pressure from the air supply header 152 by way of normally open valve 168 through the conduit 166 and to the conduit 162 connected to the port 160 disposed in the casing 132 of the pressure comparator means 130. The air pressure introduced through the port 116 enters the chamber 136 within the casing 132 moving the flexible diaphragm 138 and activator arm 146 so that the activator arm switches the valve 158. As described above, the switching of the valve 158 supplies air pressure to the header 176 and to the operator of the valve 116 commencing the automatic sequence which opens the choke 24 and stores the hydraulic fluid displaced from the hydraulic cylinder means 50 in the memory accumulator 90. The test valve 164 is then manually returned to its original position so that the air pressure is exhausted from the chamber 136 within the pressure comparator means and the stored hydraulic fluid transferred back into the hydraulic cylinder means 50 returning the choke 24 to its original setting, etc.

As will be understood by those skilled in the art, the connection of the conduits 64 and 66 to the ports 60 and 62 of the hydraulic cylinder means 50 can be reversed so that instead of opening the choke 24 upon the receipt of a physical signal indicating an over-pressure llll condition, the apparatus 26 closes the choke 24. Numerous other changes and arrangements of the various parts of the apparatus 26 will readily suggest themselves to those skilled in the art. For example, the piston 94 disposed in the memory accumulator means 90 can be urged toward the end 91 thereof and into contact with the valve 98 using spring biasing means or a variety of other means. In addition, as stated above, a variety of conventional control instruments can be substituted for the pressure comparator means 130 and the valve 158 adapting the apparatus 26 to receive and respond to signals other than pressure such as temperature, composition, etc. Thus, the apparatus 26 and method carried out by the apparatus for manually positioning a device, but automatically moving the device to a different desired position in response to a physical signal and repositioning the device to its original setting upon termination of the signal is to be limited only by the lawful scope of the appended claims.

What is claimed is:

1. Positioner apparatus for positioning a device manually, but automatically moving the device to a different desired position in response to a physical signal, and then repositioning the device to the original setting thereof upon the withdrawal of said physical signal comprising:

a. a hydraulic cylinder having a movable piston disposed therein operably connected to said device;

b. a source of pressurized hydraulic fluid;

c. first conduit means connecting said source of pressurized hydraulic fluid to opposite ends of said hy draulic cylinder;

(1. first valve means disposed in said first conduit means for manually introducing or withdrawing pressurized hydraulic fluid into and from said hydraulic cylinder so that said piston can be selectively moved to desired positions therein;

e. accumulator means for temporarily storing hydraulic fluid;

f. second conduit means connected between said accumulator means and a selected end of said hydraulic cylinder;

g. second valve means disposed in said second conduit means for selectively causing hydraulic fluid displaced from said hydraulic cylinder to be transferred into said accumulator means or hydraulic fluid stored in said accumulator means to be transferred back into said hydraulic cylinder; and

h. control means responsive to said physical signal and operably connected to said first and second valve means so that upon receipt of said physical signal said valve means are operated to cause said pressurized hydraulic fluid to be introduced by way of said first conduit means into a selected end of said hydraulic cylinder thereby moving said piston in a desired direction and hydraulic fluid displaced by the movement of said piston to be transferred by way of said second conduit means into said accumulator means, and upon the withdrawal of said physical signal, the hydraulic fluid stored in said accumulator means to be transferred back into the end of said hydraulic cylinder from which it was displaced thereby restoring said piston to the position it occupied prior to the receipt of said physical signal.

2. The apparatus of claim 1 wherein said accumulator means for temporarily storing hydraulic fluid comprises:

an elongated cylinder having a forward end and a rearward end and having a movable piston disposed therein;

means connected to the rearward end of said cylinder for urging said piston toward the forward end thereof; and

said second conduit means being connected to the forward end of said cylinder so that when displaced hydraulic fluid is introduced thereinto said piston is moved from the forward end toward the rearward end thereof and when hydraulic fluid is withdrawn therefrom said piston is moved back to the forawrd end thereof by said means urging said piston toward the forward end thereof.

3. The apparatus of claim 2 wherein said means for urging said piston toward the forward end of said cylinder comprises:

third conduit means connected to said source of pressurized hydraulic fluid and to the rearward end of said cylinder; and

third valve means for introducing or withdrawing said pressurized hydraulic fluid into and from said rearward end of said cylinder operably connected to said control means whereby when displaced hydraulic fluid is introduced into the forward end of said cylinder, hydraulic fluid is withdrawn from the rearward end thereof, and when stored hydraulic fluid is withdrawn from the forward end of said cylinder, pressurized hydraulic fluid is introduced into the rearward end thereof.

4. The apparatus of claim 3 wherein said control means responsive to said physical signal comprises:

means for receiving said physical signal and generating a first control signal in response thereto, said first control signal being operably connected to said first, second and third valve means; and

means for generating a second control signal operably connected to said piston disposed in said elongated cylinder whereby said second control signal is generated when said piston occupies positions within said cylinder other than at the forward end thereof, said second control signal being operably connected to said first and second valve means so that upon withdrawal of said physical signal and said first control signal, said second control signal maintains said first and second valve means in the same position as did the first control signal until the hydraulic fluid stored in said cylinder is displaced therefrom and said piston occupies a position at the forward end of said cylinder.

5. Positioner apparatus for controlling the operation of a device in response to a physical signal, said apparatus having the capability of automatically repositioning to an original setting which comprises:

a. first hydraulic cylinder means having a movable piston disposed therein operably connected to said d. first valve means disposed in said first conduit means for selectively introducing or withdrawing pressurized hydraulic fluid into and from said first hydraulic cylinder means so that said piston can be selectively moved to desired positions therein;

e. second hydraulic cylinder means having first and second ends and a movable piston disposed therein;

f. means attached to said second hydraulic cylinder means for urging said movable piston toward the first end thereof;

g. second conduit means connected to the first end of said second hydraulic cylinder means and to a selected end of said first hydraulic cylinder means;

h. second valve means disposed in said second conduit means for selectively causing hydraulic fluid displaced from said first hydraulic cylinder means by the movement of said piston therein to be transferred through said second conduit means into said second hydraulic cylinder means;

i. control means responsive to said physical signal and operably connected to said first and second valve means so that upon receipt of said physical signal said valve means are operated to cause said pressurized hydraulic fluid to be introduced by way of said first conduit means into a selected end of said first hydraulic cylinder means thereby moving the piston disposed therein in a desired direction, and to cause hydraulic fluid displaced by the movement of said piston to be transferred by way of said second conduit means into said second hydraulic cylinder means moving the piston disposed therein toward the second end thereof, and upon the withdrawal of said physical signal, the hydraulic fluid stored in said second hydraulic cylinder means is caused by said means urging said piston therein toward the first end thereof to be transferred back into said first hydraulic cylinder means thereby restoring said piston disposed therein to the position it occupied prior to the receipt of said physical signal.

6. The apparatus of claim wherein the means for urging said movable piston in said second hydraulic cylinder means toward the first end thereof comprises:

third conduit means connected to said source of pressurized hydraulic fluid and to the second end of said second hydraulic cylinder means; and

third valve means disposed in said third conduit means and operably connected to said control means for introducing or withdrawing pressurized hydraulic fluid into and from the second end of said second hydraulic cylinder means whereby when displaced hydraulic fluid from said first hydraulic cylinder means is introduced into the first end of said second hydraulic cylinder means, hydraulic fluid is withdrawn from the second end thereof, and when the stored hydraulic fluid is withdrawn from the first end of said second hydraulic cylinder means, said pressurized hydraulic fluid is introduced into the second end thereof.

7. The apparatus of claim 6 wherein said source of pressurized hydraulic fluid comprises:

an accumulator for containing a supply of hydraulic fluid including inlet and outlet connections;

pump means for generating a stream of pressurized hydraulic fluid having suction and discharge connections; and

conduit means connected between the outlet connection of said accumulator and the suction connection of said pump means.

8. The apparatus of claim 7 which is further characterized to include fifth conduit means connected between the inlet connection of said hydraulic fluid accumulator and to said first, second and third valve means so that pressurized hydraulic fluid withdrawn from said first and second hydraulic cylinder means is caused to be returned to said hydraulic fluid accumulator by way of said fifth conduit means.

9. A method of automatically changing the position of a device operated by manually controllable hydraulic cylinder means which includes a movable piston connected to said device in response to a physical signal, and then repositioning said device to its original setting upon the withdrawal of said physical signal comprising the steps of:

a. generating a control signal in response to said physical signal;

b. utilizing said control signal to operate the movable piston of said hydraulic cylinder means whereby pressurized hydraulic fluid is introduced into said hydraulic cylinder means on a selected side of said movable piston therein to move said piston in a desired direction and to displace hydraulic fluid from the other side of said piston;

c. storing the hydraulic fluid displaced from'said hydraulic cylinder means throughout the duration of said physical signal; and

d. then reintroducing said stored hydraulic fluid into said hydraulic cylinder means on the side of said piston from which it was displaced thereby restoring said piston to the position it occupied prior to the receipt of said physical signal.

10. The method of claim 9 wherein the step of storing said displaced hydraulic fluid is further defined to include the step of:

introducing said displaced hydraulic fluid into one end of an elongated cylinder having a movable piston disposed therein so that said piston is moved toward the opposite end of said cylinder by said fluid and said fluid is stored therein.

1 l. The method of claim 10 wherein the step of reintroducing said stored hydraulic fluid into said hydraulic cylinder means is further defined to include the step of:

returning said piston disposed in said elongated cylinder to the position it occupied prior to the introduction of said displaced hydraulic fluid therein thereby displacing said stored hydraulic fluid from said elongated cylinder into said hydraulic cylinder means. 

1. Positioner apparatus for positioning a device manually, but automatically moving the device to a different desired position in response to a physical signal, and then repositioning the device to the original setting thereof upon the withdrawal of said physical signal comprising: a. a hydraulic cylinder having a movable piston disposed therein operably connected to said device; b. a source of pressurized hydraulic fluid; c. first conduit means connecting said source of pressurized hydraulic fluid to opposite ends of said hydraulic cylinder; d. first valve means disposed in said first conduit means for manually introducing or withdrawing pressurized hydraulic fluid into and from said hydraulic cylinder so that said piston can be selectively moved to desired positions therein; e. accumulator means for temporarily storing hydraulic fluid; f. second conduit means connected between said accumulator means and a selected end of said hydraulic cylinder; g. second valve means disposed in said second conduit means for selectively causing hydraulic fluid displaced from said hydraulic cylinder to be transferred into said accumulator means or hydraulic fluid stored in said accumulator means to be transferred back into said hydraulic cylinder; and h. control means responsive to said physical signal and operably connected to said first and second valve means so that upon receipt of said physical signal said valve means are operated to cause said pressurized hydraulic fluid to be introduced by way of said first conduit means into a selected end of said hydraulic cylinder thereby moving said piston in a desired direction and hydraulic fluid displaced by the movement of said piston to be transferred by way of said second conduit means into said accumulator means, and upon the withdrawal of said physical signal, the hydraulic fluid stored in said accumulator means to be transferred back into the end of said hydraulic cylinder from which it was displaced thereby restoring said piston to the position it occupied prior to the receipt of said physical signal.
 2. The apparatus of claim 1 wherein said accumulator means for temporarily storing hydraulic fluid comprises: an elongated cylinder having a forward end and a rearward end and having a movable piston disposed therein; means connected to the rearward end of said cylinder for urging said piston toward the forward end thereof; and said second conduit means being connected to the forward end of said cylinder so that when displaced hydraulic fluid is introduced thereinto said piston is moved from the forward end toward the rearward end thereof and when hydraulic fluid is withdrawn therefrom said piston is moved back to the forawrd end thereof by said means urging said piston toward the forward end thereof.
 3. The apparatus of claim 2 wherein said means for urging said piston toward the forward end of said cylinder comprises: third conduit means connected to said source of pressurized hydraulic fluid and to the rearward end of said cylinder; and third valve means for introducing or withdrawing said pressurized hydraulic fluid into and from said rearward end of said cylinder operably connected to said control means whereby when displaced hydraulic fluid is introduced into the forward end of said cylinder, hydraulic fluid is withdrawn from the rearward end thereof, and when stored hydraulic fluid is withdrawn from the forward end of said cylinder, pressurized hydraulic fluid is introduced into the rearward end thereof.
 4. The apparatus of claim 3 wherein said control means responsive to said physical signal comprises: means for receiving said physical signal and generating a first control signal in response thereto, said first control signal being operably connected to said first, second and third valve means; and means for generating a second control signal operably connected to said piston disposed in said elongated cylinder whereby said second control signal is generated when said piston occupies positions within said cylinder other than at the forward end thereof, said second control signal being operably connected to said first and second valve means so that upon withdrawal of said physical signal and said first control signal, said second control signal maintains said first and second valve means in the same position as did the first control signal until the hydraulic fluid stored in said cylinder is displaced therefrom and said piston occupies a position at the forward end of said cylinder.
 5. Positioner apparatus for controlling the operation of a device in response to a physical signal, said apparatus having the capability of automatically repositioning to an original setting which comprises: a. first hydraulic cylinder means having a movable piston disposed therein operably connected to said device; b. a source of pressurized hydraulic fluid; c. first conduit means connecting said source of pressurized hydraulic fluid to opposite ends of said first hydraulic cylinder; d. first valve means disposed in said first conduit means for selectively introducing or withdrawing pressurized hydraulic fluid into and from said first hydraulic cylinder means so that said piston can be selectively moved to desired positions therein; e. second hydraulic cylinder means having first and second ends and a movable piston disposed therein; f. means attached to said second hydraulic cylinder means for urging said movable piston toward the first end thereof; g. second conduit means connected to the first end of said second hydraulic cylinder means and to a selected end of said first hydraulic cylinder means; h. second valve means disposed in said second conduit means for selectively causing hydraulic fluid displaced from said first hydraulic cylinder means by the movement of said piston therein to be transferred through said second conduit means into said second hydraulic cylinder means; i. control means responsive to said physical signal and operably connected to said first and second valve means so that upon receipt of said physical signal said valve means are operated to cause said pressurized hydraulic fluid to be introduced by way of said first conduit means into a selected end of said first hydraulic cylinder means tHereby moving the piston disposed therein in a desired direction, and to cause hydraulic fluid displaced by the movement of said piston to be transferred by way of said second conduit means into said second hydraulic cylinder means moving the piston disposed therein toward the second end thereof, and upon the withdrawal of said physical signal, the hydraulic fluid stored in said second hydraulic cylinder means is caused by said means urging said piston therein toward the first end thereof to be transferred back into said first hydraulic cylinder means thereby restoring said piston disposed therein to the position it occupied prior to the receipt of said physical signal.
 6. The apparatus of claim 5 wherein the means for urging said movable piston in said second hydraulic cylinder means toward the first end thereof comprises: third conduit means connected to said source of pressurized hydraulic fluid and to the second end of said second hydraulic cylinder means; and third valve means disposed in said third conduit means and operably connected to said control means for introducing or withdrawing pressurized hydraulic fluid into and from the second end of said second hydraulic cylinder means whereby when displaced hydraulic fluid from said first hydraulic cylinder means is introduced into the first end of said second hydraulic cylinder means, hydraulic fluid is withdrawn from the second end thereof, and when the stored hydraulic fluid is withdrawn from the first end of said second hydraulic cylinder means, said pressurized hydraulic fluid is introduced into the second end thereof.
 7. The apparatus of claim 6 wherein said source of pressurized hydraulic fluid comprises: an accumulator for containing a supply of hydraulic fluid including inlet and outlet connections; pump means for generating a stream of pressurized hydraulic fluid having suction and discharge connections; and conduit means connected between the outlet connection of said accumulator and the suction connection of said pump means.
 8. The apparatus of claim 7 which is further characterized to include fifth conduit means connected between the inlet connection of said hydraulic fluid accumulator and to said first, second and third valve means so that pressurized hydraulic fluid withdrawn from said first and second hydraulic cylinder means is caused to be returned to said hydraulic fluid accumulator by way of said fifth conduit means.
 9. A method of automatically changing the position of a device operated by manually controllable hydraulic cylinder means which includes a movable piston connected to said device in response to a physical signal, and then repositioning said device to its original setting upon the withdrawal of said physical signal comprising the steps of: a. generating a control signal in response to said physical signal; b. utilizing said control signal to operate the movable piston of said hydraulic cylinder means whereby pressurized hydraulic fluid is introduced into said hydraulic cylinder means on a selected side of said movable piston therein to move said piston in a desired direction and to displace hydraulic fluid from the other side of said piston; c. storing the hydraulic fluid displaced from said hydraulic cylinder means throughout the duration of said physical signal; and d. then reintroducing said stored hydraulic fluid into said hydraulic cylinder means on the side of said piston from which it was displaced thereby restoring said piston to the position it occupied prior to the receipt of said physical signal.
 10. The method of claim 9 wherein the step of storing said displaced hydraulic fluid is further defined to include the step of: introducing said displaced hydraulic fluid into one end of an elongated cylinder having a movable piston disposed therein so that said piston is moved toward the opposite end of said cylinder by said fluid and said fluid is stored therein.
 11. The method of claim 10 wherein the steP of reintroducing said stored hydraulic fluid into said hydraulic cylinder means is further defined to include the step of: returning said piston disposed in said elongated cylinder to the position it occupied prior to the introduction of said displaced hydraulic fluid therein thereby displacing said stored hydraulic fluid from said elongated cylinder into said hydraulic cylinder means. 